Electromechanical switching devices for switching electrical currents are known in the prior art. One class of such electromechanical switching devices is that of devices known as circuit breakers. These circuit breakers comprise a housing in which the individual phases of the currents are switched. The individual phases may be accommodated in pole cassettes, which are enclosed by a housing. Accommodated in the pole cassettes are movable and fixed contacts, which can be moved apart for opening a circuit and brought into contact for closing the circuit.
In circuit breakers, for example compact circuit breakers, generally multiple individual pole cassettes are interconnected and mechanically connected to one another. In the pole cassettes, movable contacts are in turn respectively arranged in a rotor housing. The respective rotor housings, which serve as carrier modules for the movable contacts, must likewise be mechanically connected to one another, so that the movable contacts can be switched on and off together. In the case of such circuit breakers, great forces act on the components of the circuit breaker or the carrier shaft located therein during switching into a TRIP position or during a switching-off operation. In order to avoid damage to the circuit breaker, components with great rigidity and great strength are required.
In the prior art, a rotating carrier shaft for carrying contact arms for a low-voltage protective switch is known for this purpose. This carrier shaft has a modular structure, which comprises along an axis of rotation at least one first carrier module and one second carrier module and a connecting module in between. In the case of the circuit breakers known in the prior art, such a connecting module usually includes plastic and is connected between the carrier modules by way of a plug-in connection of the male-female type. However, such a connecting module of plastic does not offer the desired rigidity between the individual carrier modules. It has also been found in practice that such connecting modules become worn relatively quickly.
Also known in the prior art are circuit breakers in which individual rotor housings are mechanically connected to one another by way of metal shafts. Although such a connection achieves a certain rigidity between the individual rotor housings, a torsion-inhibiting connection of metal does however have disadvantageous effects on the overall weight of the circuit breaker.